HELP!!Why and How to solve this linking errors.

What's wrong?Please help!

No compile error but I got this linking errors :-

Code:

Compiling...
main.cpp
Linking...
Test_Display.obj : error LNK2001: unresolved external symbol "public: void __thiscall Test_Text::test_put_text(char *)" (?test_put_text@Test_Text@@QAEXPAD@Z)
Test_Display.obj : error LNK2001: unresolved external symbol "public: void __thiscall Test_Display::test_put_display(char *)" (?test_put_display@Test_Display@@QAEXPAD@Z)
Test_Display.obj : error LNK2001: unresolved external symbol "public: void __thiscall Test_Indicator::test_put_indicator(char *)" (?test_put_indicator@Test_Indicator@@QAEXPAD@Z)
Debug/H1.exe : fatal error LNK1120: 3 unresolved externals
Error executing link.exe.

H1.exe - 4 error(s), 0 warning(s)

Here are the .cpp and .h files:-

Code:

1) Test_Display.h

#ifndef TEST_DISPLAY_H
#define TEST_DISPLAY_H

#include "Sum_Class.h"

class TestDisplay
{
	public:
		TestDisplay();
		TestDisplay(int);
		void put_text (char *text);
		void put_indicator (char *text);
		void put_display (char *text);


	private:
		Test_Indicator* m_ptr_ind;
		Test_Text* m_ptr_text;
		Test_Display* m_ptr_display;

};

#endif TEST_DISPLAY_H

Code:

2) Test_Display.cpp

#include <iostream.h>
#include "Test_Display.h"
#include "Sum_Class.h"

TestDisplay::TestDisplay (int displayType)
{
		m_ptr_ind = new Test_Indicator(displayType);
		m_ptr_text = new Test_Text(displayType);
                                m_ptr_display = new Test_Display(displayType);

		
}



void TestDisplay::put_text (char *text)
{
	m_ptr_text->test_put_text(text);
}

void TestDisplay::put_display (char *text)
{
	m_ptr_display->test_put_display(text);
}

void TestDisplay::put_indicator (char *text)
{
	m_ptr_ind->test_put_indicator(text);
}

Code:

3) Sum_Class.h

#ifndef SUM_CLASS_H
#define SUM_CLASS_H


class Test_Text 
{
  public:
               Test_Text(int x) {display_id = x;}
	void test_put_text(char *str);
  private:
	int display_id;
	
};

class Test_Display 
{
  public:
	  Test_Display(int x) {display_id = x;}
	  void test_put_display(char *str);
  private:
	int display_id;

};

class Test_Indicator 
{
  public:
	  Test_Indicator(int x) { display_id = x;}
	  void test_put_indicator(char *str);
  private:
	int display_id;

};

  
#endif // SUM_CLASS_H

Code:

4) main.cpp

#include <iostream.h>
#include "Test_Display.h"

#define TOP 0
#define FRONT 1

void main(void)
{
	TestDisplay *TestArr[2];

	TestArr[TOP] = new TestDisplay(TOP);
	TestArr[FRONT] = new TestDisplay(FRONT);
	

}

Wheres the implementation of those functions? You have only posted the declarations in Sum_Class.h

Oh yeah!very good question!
Your question solved my problem
After adding the implementation for the functions in Sum_Class.h, problem solved!!
Thanks a lot!!

Oh, and by the way, use int main() instead of void main(void).